In upstream oil and gas supply applications, oil is stored in a variety of storage tanks. During the transport of the oil from the tank to the upstream application, flammable gasses may be generated which are burned off by gas flares or flare stacks. At times, the velocity of vapors flowing towards the flare may be low enough to allow the flame from the flare to travel into the pipe in the opposite direction. Potentially catastrophic failures may occur if the flame is allowed to reach the storage tank.
Additionally, damaging detonations may occur in which the flame rapidly propagates the flow path in a manner resembling a shockwave. These detonations are oftentimes caused by turbulence-creating geometries such as bends, sharp turns, and other interruptions to the flow path.
To mitigate this risk, flame, detonation, and/or deflagration arrestors may be implemented and disposed between the storage tank and the gas flare. In the event that a flame propagates towards the storage tank, these flame arrestors block the flame from further advancing to the storage tank. However, these flame arrestors have a limited useful life and their performance can be compromised upon being exposed to flames for extended periods of time, as each arrestor is designed to withstand a “sustained burn” for a certain period of time. This period of time may be anywhere between minutes to several hours, depending on the arrestor. If a sustained burn lasts longer than the arrestor is rated for, there is a chance that the arrestor will fail if the flow is not shut off to extinguish the flame. Further, these flame arrestors may not be suitable to contain or limit flames caused by detonations due to their rapid propagation. Further still, when employed in remote locations, these devices may be difficult to inspect, thus any degradation in quality may not be realized. In other examples, early detection equipment such as temperature detection sensors and the like are also frequently used in these environments. However, this equipment may experience similar pitfalls due to being positioned in remote locations.
Thermal valves may be implemented to restrict the backwards propagation of gases towards the storage tank by limiting the supply of flame-generating fluids. However, conventional thermal valves may have configurations conducive to generating turbulence along the flow path, which in turn may lead to detonations.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.